Data from: Contrasting ecological roles of non-native ungulates in a novel ecosystem
Gawel, Ann Marie, Iowa State University
Rogers, Haldre S., Iowa State University
Miller, Ross H., University of Guam
Kerr, Alexander M., University of Guam
Published Oct 30, 2017 on Dryad.
Cite this dataset
Gawel, Ann Marie; Rogers, Haldre S.; Miller, Ross H.; Kerr, Alexander M. (2017). Data from: Contrasting ecological roles of non-native ungulates in a novel ecosystem [Dataset]. Dryad. https://doi.org/10.5061/dryad.sp5ff
Conservation has long focused on preserving or restoring pristine ecosystems. However, understanding and managing novel ecosystems has grown in importance as they outnumber pristine ecosystems worldwide. While non-native species may be neutral or detrimental in pristine ecosystems, it is possible that even notorious invaders could play beneficial or mixed roles in novel ecosystems. We examined the effects of two long-established non-native species – Philippine deer (Rusa marianna) and feral pigs (Sus scrofa) – in Guam, Micronesia, where native vertebrate frugivores are functionally absent leaving forests devoid of seed dispersers. We compared the roles of deer and pigs on seedling survival, seed dispersal, and plant community structure in limestone karst forests. Deer, even at low abundances, had pronounced negative impacts on forest communities by decreasing seedling and vine abundance. In contrast, pigs showed no such relationship, and more seeds were found in pig scats than deer scats, suggesting that pigs provide an ecosystem function – seed dispersal – that has been lost from Guam. Our study presents a surprising discrepancy between the roles of two non-native species that are traditionally managed as a single entity, suggesting that ecological function, rather than identity as a non-native, may be more important to consider in managing novel systems.
Guam seedling plots
Survival or mortality of set of six species planted in fenced and unfenced seedling plots.
Scat germination and forest species
Data used to calculate proportions of seedlings of given species that germinated from collected scat and compare that information to proportion of adult trees that could have been seeding in forests from which scats were collected.
Vegetation and scat transect
Belt transects in forest, with counts and identification of all seedlings and adult plants and counts of pig and deer scat used for abundance indices.
Script for seedling plots
Code for model selection analyses and figure about seedling survival in fenced compared to unfenced plots.
Script for seedling plots that include time
Script containing code for information and plots in supplementary information using data from seedling plots.
Script for species in scat vs species in forest
Script containing code for two-panel plot showing differences in species abundance in nature versus species abundance in deer and pig scats, separating native and non-native plant species.
scat germ vs forest.R
Script for ungulate and forest abundance regressions
Script containing code for linear model selection, regression, and multipanel figure showing regression of forest abundances and ungulate scat counts.
Supplementary script for ungulate and forest abundance regressions
Script to exclude highest extreme values of ungulate abundance and to replicate analyses and figures showing regression of forest abundances and ungulate scat counts.